As promised, in a follow up to our blog on pallet flow height considerations, we’d like to offer some guidance to another popular question, “How deep can I build my pallet flow rack?” Again, a seemingly simple question, but with an answer that is unique for each customer’s application. For this blog, we will focus on the considerations that go into determining optimal pallet flow system depth.
The basic formula for pallet flow rack depth is straight forward… # of pallets deep X pallet depth + 12”, plus load overhang if applicable. This is the easy part. The next step is to evaluate a number of variables, from building specs to lift truck capacities, which will impact the depth of your system.
Major Variables for Determining Pallet Flow Rack Depth
- Building Parameters
- Load & System Variables
- M H Equipment/Trucks
Let’s take a look at each of these individually. The building parameters are an obvious place to start. With a thorough review of the building layout and the intended use of the pallet flow (i.e. staging, manufacturing, picking) we can identify the most efficient loading and unloading areas of the flow rack and establish a range for the depth of the system.
- Building dimensions
- Dock area dimensions/restrictions
- Fire code regulations & systems
Once we know physically how deep a system can go within the confines of the building, we determine the optimum pallet flow rack depth using load and system speculations.
Load and System Specs
- Load weigh
- Pallet type & condition
- SKU mix
Load Weight – When considering the load weight, use the max load for pallet flow design. Weight will have an impact on the type of pallet flow, beam selection and the pitch.
Pallet Type & Quality – While we are discussing design, it is always critical to remember the importance of pallet quality; good quality GMA pallets for use in pallet flow will help prevent hang-ups and system or product damage. In order for a 5, 10, 15 or greater depth system to flow optimally the pallet is as important as the wheels, pitch and overall construction.
Pitch – Once again, pitch is set on a customer by customer basis by Mallard using load weight, truck capacities (which we will get to in a moment) and product composition. It is important to note however, that pitch increases with depth impacting level height and overall system height.
SKU Mix – Before deciding the depth of your pallet flow rack, you should have a good understanding of your SKU mix to determine inventory requirements and pallet density per SKU within the system.
Material Handling Equipment
What kind of material handling equipment will be used to access the system is our next area of review. The type of truck and its respective max height and capacity requirements must be considered in your system design. Within the capacity allowance, be sure to consider the possibility of significant back pressure when unloading a deep-lane pallet flow system.
Back Pressure Formula – Back pressure is approximately 6% of the full weight of the rear pallet loads.
Ex) 5-deep system with 2,500 lb. loads –
Back pressure = .06 x 2,500 lbs. x 4 pallets = 600 lbs.
Note: Ask about pallet separators used to hold back rear pallets and relieve these rear pallet forces.
Truck Derating – Also make sure to review truck manufacturer specs for deration; the decrease in truck’s nominal capacity due to lift height. You’ll have to account for this deration at higher pallet flow levels.
If you are considering a pallet flow system for your business and need some design help – contact one of our pallet flow specialists, they are ready to help.
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